The researchers found that parasites affecting humans were as likely to face extinction as those that target other species. However, there was one group of parasitic worms—Acanthocephla—that faced fewer threats than the other groups. These worms don't usually infect people; their specialty is fish, amphibians, invertebrates, birds and other mammals. The researchers weren't sure exactly why these wrigglers seemed to fare better than other parasites in the models—they may just be geographically lucky. But co-author Anna Phillips says that this strange exception to the rest of the study brought up an important point for her. "We wanted to address parasite diversity on the whole, not just what affects humans," she says. Scientists estimate that 86 to 99.999 percent of species remain undiscovered, and parasites aren't the most glamorous organisms to put your name on. Extinctions will affect ecosystems that we do not yet understand, which makes it impossible to know how other creatures will be impacted. Even for species we're already familiar with, the domino effects remain unclear.